DATASET habitat_rar_20020916_ll_gda94

  Title

Marine Habitats of the Recherché Archipelago

  Custodian

 Department of Conservation and Land Management (CALM)

  Jurisdiction

 Western Australia

DESCRIPTION

  Abstract

 This dataset consists of polygons detailing the offshore marine habitats of Southern Western Australia's Recherché Archipelago and covers an area extending from Stokes Inlet (121oE) eastward to Israelite Bay (124o15'E) and seawards to Western Australia's Coastal Waters boundary. 

  Search Word(s)

 

Geographic Extent Name(s) 

 WA South Coast (WSC) and Eucla (EUC) IMCRA regions

DATA CURRENCY

  Begin Date

 August 2002

  End Date

 

DATASET STATUS

  Progress

 In Progress

  Maintenance & Update Frequency

As required

ACCESS

  Stored Data Format

 DIGITAL ArcView shapefile, unprojected   - Geocentric Datum of Australia 1994 (GDA94). 

  Available Format Type

 DIGITAL ArcView 3.2 shapefile

  Access Constraint

Data available for external use subject to transfer fee and license conditions.
Data is not to be distributed without authorisation from CALM. 
Contact CALM's database administrator for further details.

DATA QUALITY

  •   Lineage
  • .
    STAGE 1 (Carried out by Kevin Bancroft July - August 2002)

    1. Initially a conceptual model for comparing the existing CSIRO ground-truth data and recently acquired ground-truth data was developed. This model is as follows :

    CONCEPTUAL MODEL
    After a comparison between the existing CSIRO ground-truth data (see Appendix C) and further ground-truth data acquired during the collaborative habitat survey (see ACTION  8, Appendix F), the following conceptual model was developed.

    Rule 1. The existing preliminary habitat map classifications are to be aligned with the latest shallow-water marine habitat classification scheme (Bancroft, in prep).  These reclassifications are listed in Table  2: 

    Table 2.  Re-assignment of marine habitat classifications
     Shallow-water marine habitat classification (Bancroft, in prep)
     
     
    Existing CSIRO assigned classifications Shallow-water marine habitat classification (Bancroft, in prep)
    Bare Mobile sand (sub tidal)
    Sparse seagrass Perennial seagrass (sparse)
    Patchy seagrass Perennial seagrass (medium)
    Medium seagrass Perennial seagrass (medium)
    Dense seagrass Perennial seagrass (dense)
    Granite  Macroalgae(subtidal, high relief)
    Heavy limestone reef  Macroalgae (sub tidal, high relief)
    Low profile reef Reef pavement (sub tidal)

    Rule 2. The preliminary habitat map polygons classified as perennial seagrass (dense), perennial seagrass (medium), perennial seagrass (sparse) or macroalgae (sub tidal, high relief) in areas <50 m bathymetry have a high level of confidence and are to remain.

    Rule 3. Areas with >50 m bathymetry are to be classified as pelagic.

    Rule 4. Between the 20 m and 50 m isobath, except where rule 2 is applied, all other existing classifications and polygons are to be ignored.

    Rule 5. The area between the 20 m and 50 m isobath is to be classified as mobile sand/reef pavement (sub tidal) with the exception of where rule 2 is applied.

    Rule 6.  In the areas of <20 m bathymetry, all existing polygons are to remain.

    Rule 7. The leeward sides of inshore islands are to be classified as perennial seagrass (medium) or perennial seagrass (dense) where ground-truth data is available.

    Rule 8 Where offshore islands have a <10 m isobath, the area between 0-10 m is to be classified as macroalgae (sub tidal, high relief).

    Rule 9 Where offshore islands have only the 20 m isobath, the area between 0-20 m is to be classified as macroalgae (sub tidal, high relief).

    Rule 10 Where offshore islands have 10 m–20 m bathymetry, in addition to where rule 8 is applied, the area is to be classified as macroalgae (sub tidal, low relief).

    Rule 11 Where islands have no related 10 m or 20 m isobath, a 50 m buffer is to be applied and classified as macroalgae (sub tidal, high relief) with the exception of where Rule 2 and rule  7 has been applied.

    Rule 12 The island areas where the DOLA coastline high water and low water marks are not supported by bathymetry and chart datasets, are to be classified as offshore intertidal reef, if the Royal Australian Navy (RAN) navigational charts or RAN point bathymetry data layer shows these areas as having <5 m in depth .  Areas having >5 m depth are to be classified as macroalgae (sub tidal, high relief).

    Rule 13 Shallower bathymetry (<10 m) in areas of <50 m bathymetry, are to be classified as macroalgae (sub tidal, high relief).

    Rule 14 The shallow water areas (<20 m) in the Eastern Group of islands, are to be classified as mobile sand/reef pavement (sub tidal). 

    Rule 15 Interpolative methods are to be used where there were three or more juxtaposed ground-truth sites classified as pebble/rubble (sub tidal).
     
    The above conceptual model was utilised to revise the preliminary broadscale map of the major marine benthic habitats in the Recherché Archipelago region (see ACTION 9)
     

    STAGE 2 (Carried out by Philip Kindleysides  August-September 2002)

    1. After undergoing a datum shift to GDA94 from AGD84, the Hugh Kirkman benthic marine habitat mapping of the south-west of WA was modified to cleanly intersect the mainland and island polygons present in the Coastline-poly_rar_2001_02_28 dataset. This was achieved by extending the relevant polygons across the coastline, unioning the two datasets and removing the overlapping polygons. The mainland and relevant island polygons from the Coastline-poly_rar_2001_02_28 dataset were then copied to the habitat dataset. 

    2. The resulting dataset was then clipped to cover only the study area set out by the outerstudyarea_rar_20020822_ll_gda94 dataset and the existing Kirkman polygons were reattributed as per Rule 1 of the conceptual model above.

    3. Areal units classified as Intertidal Offshore (Rule 12) by Kevin Bancroft were sourced from coastline-poly_lwm_rar_20010228_ll_gda94 which is a modified DOLA coastline (28 Feb 2001). The Dola dataset was limited to the study area and low water mark records and projected to MGA zone 51. A clean polylines and build polylines (5m threshold) series of operations were performed and the dataset was reverted to lat. and long. 

    4. Further areal units from the bathymetry_rar_ll_gda dataset were cut and pasted into the habitat dataset in question. These were attributed as per the conceptual model above.

    5. Where required by the conceptual model, a 50m buffer operation was performed on island and low water mark  polygons in the habitat dataset. The resulting halo polygons were attributed as per the conceptual model above and if necessary clipped by the existing Kirkman polygons.  Several areal units were manually digitised based upon visual and ground truth reference points. 

    6. Conceptual model firmed via cross referencing ground truth data from the habitat database and gtsites_kb_rar_2002_ll_gda94 dataset.

    7. Where small generated polygons were inconsistent with the original broad Kirkman or the above conceptual model, they were reattributed to preserve a logical consistency.

    8. As per rule 4 and 5, in the above conceptual model, the following steps were performed. 20m to 50m polygons from the bathymetry_rar_ll_gda dataset were unioned with the habitat dataset. Only the mutually inclusive polygons and those meeting rule 2, were kept and the resulting area was erased from the habitat dataset. The cleared area in the habitat dataset was then replaced by the unioned dataset and the relevant attribute changes were made. i.e. 20m to 50m areas containing mobile sand or reef pavement (sub tidal) were replaced with a joint category of mobile sand/ reef pavement (sub tidal). 

    9.  Data datum transformed from AGD84 to GDA94 using the change datum functionality of the extension 'CALM Added Functionality v2000' in Arcview3.2.
     

     Positional Accuracy

    Habitat extents were delineated as accurately as is possible to determine from the available digital and hardcopy sources. Further Ground-truthing would need to be undertaken to determine them with greater accuracy.

      Attribute Accuracy

      Logical Consistency


    Attribute values have been checked and validated for consistency, and checked for logic in relation to attribute names. All attributes that require values have had values assigned.

    The shapefile has been compiled carefully to avoid overlaps or duplication of points.

    Completeness

     The dataset will be upgraded as priorities, time and resources permit. 
    Further work needs to be undertaken on ground-truthing.

    CONTACT INFORMATION

      Contact Organisation

     Department of Conservation and Land Management, Marine Conservation Branch

      Contact Position

     Marine GIS Co-ordinator

      Mail Address 1

     47 Henry Street

      Mail Address 2

      Suburb or Place or Locality

     Fremantle

      State or Locality 2

     WA

      Country

     Australia

      Postcode

     6160

      Telephone

     08 9336 0109

      Facsimile

     08 9430 5408

      Electronic Mail Address

     rayl@calm.wa.gov.au

    METADATA DATE

      Metadata Date

     5 June 2002

    ADDITIONAL METADATA

      Additional Metadata

    - For further information on data sources and methods, refer to: Bancroft K.P. (2002).  Establishing a marine protected area in the Recherché Archipelago region.  Year 1: The physical and biological information requirements.  Final Report: MRI/WSC,EUC/RAR,SIN-59/2002.  August 2002.  Marine Conservation Branch, Department of Conservation and Land Management, Fremantle, Western Australia. 
    - See accompanying habitat classification documentation further describing the classification system held by CALMs Marine Conservation Branch (see SMECCS_291101.doc).
    NOTE: This system is still in development. Any feedback would be appreciated.